miR-200a在DEHP暴露致骨骼肌胰岛素抵抗过程中的调控机制研究

项目名称： miR-200a在DEHP暴露致骨骼肌胰岛素抵抗过程中的调控机制研究

项目编号： No.81502782

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 医药、卫生

项目作者： 魏杰

作者单位： 厦门大学

项目金额： 18万元

中文摘要： DEHP暴露是胰岛素抵抗的风险因素之一，但作用机制研究报道较少。miRNA作为内源性小分子RNA，可通过调控胰岛素信号通路参与胰岛素抵抗的发生。骨骼肌是胰岛素抵抗发生的主要部位。前期研究发现，DEHP暴露导致小鼠骨骼肌中miR-200a表达及胰岛素刺激下Akt磷酸化水平显著变化。所以，本项目拟以C57BL/6小鼠和C2C12细胞株为研究对象，系统分析DEHP暴露致骨骼肌胰岛素抵抗发生的时程和量效规律；研究DEHP暴露对骨骼肌PI3K/Akt胰岛素信号通路的影响；探讨DEHP暴露诱导骨骼肌miR-200a表达变化的规律和特点；筛查DEHP暴露诱导骨骼肌PI3K/Akt信号通路转导阻滞过程中受miR-200a调控的靶基因并构建miR-200a-mRNA相互作用的分子调控网络；最终揭示DEHP暴露诱导骨骼肌胰岛素抵发生的分子机制。本项目有望找到DEHP暴露致胰岛素抵抗发生的潜在生物标志物。

中文关键词： 邻苯二甲酸二（2-乙基己基）酯；微小RNA；miR-200a；胰岛素抵抗；骨骼肌

英文摘要： Di-(2-ethylhexyl) phthalate (DEHP) is one of the ubiquitous environmental endocrine disruptors, which is widely used as plasticizers in food packaging, children’s products, medical devices, household products and industrial plastic, etc. Human can be continuously and inevitably exposed to DEHP from multiple sources. Recently, growing evidence has indicated that exposure to DEHP is associated with an increased risk of insulin resistance, but the underlying molecular mechanisms are limited. MicroRNA (miRNA) is a group of single stranded small non-coding RNA, which has a critical role in posttranscriptional regulation of key genes involved in insulin signaling pathway, contributing to the development of insulin resistance. Skeletal muscle has been considered to be a major regulator of systemic glucose homeostasis. In our present study, we found that exposure to DEHP (2 or 20 mg/kg/day) induced insulin resistance and decreased the insulin-induced phosphorylation of AKT (S473/T308) in skeletal muscle in C57BL/6 mice. Moreover, expression of miR-200a was increased in the DEHP-exposed skeletal muscle. Bioinformatics-based studies suggested that 3’UTR of some key insulin signaling genes, such as Igf1r, Insr, Irs1 and pik3r1, are targets of miR-200a, so we hypothesized that miR-200a is a critical regulator of DEHP-induced insulin resistance in skeletal muscle. In the present study, we generated in-vivo mice model and in-vitro cell line model to test whether exposure to DEHP was able to induced insulin resistance in skeletal muscle, and if so, whether these adverse effects were mediated by impaired regulation of miR-200a-PI3K/Akt signaling pathway. We firstly tested the effects of exposure to DEHP on the whole-body glucose homeostasis and the components/modulators of PI3K/Akt insulin signaling pathway in skeletal muscle; and moreover, investigated the dose/time/response relationship. Then, we determined the expression pattern of miR-200a in DEHP-exposed skeletal muscle; screened and identified miR-200a regulated essential target genes in PI3K/Akt insulin signaling pathway network. After that, intervention experiments were performed to ensure the possibility that exposure to DEHP impaired insulin signaling in skeletal muscle by selectively regulation of miR-200a-PI3K/Akt interaction network. Taken together, this study is expected to address the mechanism of DEHP-induced insulin resistance at molecular levels, and furthermore, to evaluate the feasibility of miRNA as biomarkers.

英文关键词： DEHP;miRNA;miR-200a;insulin resistance;skeletal muscle